Entity Data Model & DataGridView - Creating new objects

I'm pretty new to the EDM, so bear with me. I have a windows form that has a DataGridView on it that's bound from the EDM I created. I figured out how to update my changes fine, but it's when the user creates a new row that I'm having a problem.

I tried numerous ways and many google searches, but came up with nothing so far.

Here's how the data is loaded:

    Dim boilerID As Integer = DirectCast(ddlBoiler.SelectedValue, Integer)
    Dim cou开发者_运维知识库ntryID As Integer = DirectCast(ddlCountry.SelectedValue, Integer)

    Dim ratings = From r In _Context.Rating _
                 Where r.Boiler.Boiler_ID = boilerID _
                 And r.Country.Country_ID = countryID _
                 Order By r.Sequence _
                 Select r

    RatingBindingSource.DataSource = ratings.ToList()

Also, all I'm doing to save the information right now is the following:

Private Sub btnSave_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnSave.Click
    _Context.SaveChanges()
End Sub

I want the user to be able to use the grid's "new row" feature to add new items to the database instead of having to click a button and open a new dialog. How would this be accomplished?

I can include some of the methods i tried for adding new items if anyone needs to see.

Thanks!

UPDATE: here's one of the methods I tried for adding new objects and the error I receive:

    For Each dgvr As DataGridViewRow In dgvRatings.Rows
        If dgvr.DataBoundItem IsNot Nothing AndAlso CType(dgvr.DataBoundItem, Rating).Rating_ID <= 0 Then

            Dim r As Rating = dgvr.DataBoundItem
            r.Boiler = ddlBoiler.SelectedItem
            r.Country = ddlCountry.SelectedItem

            _Context.AddObject("Rating", r)
        End If
    Next

Error (occurs when calling _Context.SaveChanges()): Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. Refresh ObjectStateManager entries.

you need to use

_Context.MyEntities.AddObject(theNewObject)

This registers the created object to be inserted when calling .SaveChanges()

You didn't give enough information to give a more complete answers, but creating a new entity, and adding it that way is what it comes down to.

Found the issue. In my stored procedure mapping, i had Rating_ID set as a Results Binding. In my stored proc I had the following:

RETURN SCOPE_IDENTITY()

Instead of:

SELECT SCOPE_IDENTITY() AS Rating_ID

I didn't think it was a stored proc issue since i knew the insert was correct (I could run the procedure by itself) and there were no records being inserted. I guess when it didn't find the Rating_ID as part of the result set, it removed the record.